The 26-year-old singer didn't start dating the Sum 41 rocker - who she split from in October 2009 after three years of marriage - until she was 19 years old but says their first encounter was incredibly memorable, though she had to be carried out" of the bar they were in.
Asked about when they met, she said: "I made out with him the first day I met him. He gave me my first shot of Jagermeister. I had a tie on - it was back in The Days of the tie. I was 17. As I was getting carried out of the bar I saw Chad from Nickelback! Isn't that funny?"
Avril - who is now in a relationship with reality TV star Brody Jenner - also revealed her Los Angeles home is inspired by European "medieval gothic castles", but she is "scared" by the size of the lavish property.
She told Rolling Stone magazine: "I decorated my house like a medieval gothic castle, European-style. Chandeliers and red velvet curtains. My bedroom is Pink and black, my bathroom is totally Hello Kitty, I have a massive pink couch and a big antique gold cross.
"I'm not gonna lie, it's 12,000 square feet. It's so big it scares me. At night I like to put on candles and jazz music, and I like to cook. Homemade spinach and ricotta ravioli, with butter-sage sauce. And I get out the wine! I like to put my TV on to the Rat Pack station; it's a music channel."